Metal and process of manufacture



Sept. 9, 1930. J, G, DONALDSON Er AL 1,775,159

METAL AND PROCESS 0F MANUFACTURE Filed nec. 21, 192e 4 sheets-sheet 1 ATTORNEY 7 Sept. 9, 1930.

J. G. DONALDSON El' AL METAL AND PROCESS OF MANUFACTURE Filed Dec. 2l, 1926 4 Sheets-Sheet 2 @M24/4v ATTORNEY Sept. 9, 1930.

Filed Dec. 21, 192e J. G. DONALDSON E' AL METAL AND PROCESS OF MANUFACTURE 4 Sheets-Sheet 3 ATTORNEY SePt- 9 1930- G. DONALDSON Er Az. 1,775,159

METALAND PROCESS OF MANUFACTURE lFiled Dec. 2l, 1926 4 Sheets-Sheet 4 INVENTOR ATTORNEY Patented Sept. 9, 1930 UNITEDv STATES PATENT OFFICE JOSEPH G. DONALDSON .AND HENRY L. GOLES, F HAMILTON, OHIO, ASSIGNORS TO GUARDIAN METALS COMPANY, OF HAMILTON, OHIO, A CORPORATION OF DELA- WARE METAL AND PROCESS OF MANUFACTURE Application led December 21, 1926. Serial No. 156,107.

This invention relates to a new metalwhich possesses .many propertles and advantages that make it of distinct value in the commercial arts. l

This new metal possesses great ductility and toughness, has higher heat conductivity and electrical/ conductivity than has heretofore been produced under like conditions, and at the same time is resistant to attacks made by means of high heat locally applied such as v the heat of the Oxy-acetylene blow torch. The

metal is especially resistant `to attacks by a cutting torch acting in conjunction with the fluXing rod or to the oxygen lance in its various forms.

This new metal is of large crystalline structure, and its purity is of a percentage not hertofore attained.

In this invention a metal, such as copper, is taken in a relatively pure condition and onlyv a relatively small change is made in its pureness, but as a result thereof there are material and marked changes in its crystalline structure and in its physical properties. Thaty is, radical changes in the vcrystalline 'struci' ture and properties are made without a particularly marked change in chemical analysis.

The accompanying drawings illustrate portions of the invention, and the preferred temperature ranges andl amounts of deoxidizing agent, and further illustrate some of the ex-A amples-of microphotographs of the metals.

In these drawings Fig. l is a chart illustrating the preferred amount of deoxidizing agent to be included atv particular temperatures for pouring;

Fig. 2 represents a preferred cooling curve for obtaining the desired results described herein; l

Fig. 3 illustrates cooling curves of metals in which various elements' have been added; and

Figs. 4, 5, an'd 6 are reproductions of microphotographs of various examples of the metals.

These marked changes in structure and properties are accomplished, inthe manner We prefer, by submitting a me al to a definite process of deoxidization, *then deliberately adding nuclei forming substances, and then The chemical composition of this amor-- phous material has not been determined.

From experiments and use, this new metal having large grain size cannot be cut with an acetylene blow torch, and if of suicient Size cannot be melted by large blow torches; and it offers exceptionally high resistance to the iiuxing action of molten iron when attacked by the cutting torch acting in conjunction with the iiuxing rod; or when attacked by the oxygen lance. The amorphous material, particularly, resists the attacks of these destructive devices.

The general process for manufacturing this new metal may be considered as above outlined, but there are, however, certain precautionswhich should be noted in order that the most efficient results may be obtained. One of these precautions is to thoroughly mix or stir` into the molten metal the deoxidizing agent so that it is thoroughly distributed throughoutl all of the metal. Thorough stirring is also desired when the nuclei forming substances are added. In addition, it has been found advantageous to cover the molten mass with a material which prevents the oxidization of the. surface metal. This covering has been found of advantage during the heating step, during the deoxidizafound that certain ,materials act as deoxidizers and at the same time act as nuclei forming substances. Carbon in the form of graphite gives such a double satisfactory action.

ln producing this new metal it is preferred to choose a metal of high conductivity, such as copper and to bring this metal to a molten condition. In practice this is preferably accomplished by using a furnace of the direct arc type, or a rotating furnace of the indirect arc type.

After the metal has beenmade molten it isv essential that the same be brought to a high degree of. deoxidization. The best results have been obtained when .the deoxidization has been particularly high. Any suitable deoxidizing "agent may be employed and it is particularly desirable in order to Y obtain ideal results to use that deoxidizer in detail.

which will remove Ithe oxides from the metal and will least alloy therewith. We

have found that `20% of commercial cupro silicon is advantageous for this purpose when copper yis used as a base metal. l/Ve have also found that carbon, preferably in the form of` powdered graphite, is most excellently suited for the deoxidization of certain metals,

especially such a metal as copper. Iny thev last instance, carbon unites with the oxygen and forms a gas (carbon monoxide or carbon dioxide) and if the metal is properly stirred the gas will escape from the mixture. The carbon in the form of graphite also performs another function as will be set forth below lf an excess of certain deoxidizers is used, an alloy will be formed between the deoxidizing agent and the metal, with the result that the conductivity of the metal will be lowered, and its resistance to heat attack locally applied consequentlylgreatly impaired.

Our experiments have shown that there is a direct relation between the heat of the metal and the amount of the deoxidizing agent which must be used. Reference is, therefore, made to Fig. 1 in which a working curve is reproduced to determine the amount of the deoxidizing agent to be used to v,give the best results when the molten material is copper at a delinite temperature. the temperature of the molten copper metal is 23000 F., the quantity of the deoxidizing agent will be .70%. Again, if the ktemperature of the molten material is 2450o F., the

quantity of the deoxidizing agent will beA .35% as will be noted from the curve. In

For instance, if

carrying out the addition of the proper amount of deoxidizer, it is assumed that a charge of 5000 lbs. is introduced into the furnace and that it has been brought to a tem- .perature of 2300 F., then the requirement of the deoxidizer of the .70% is added'. We

now assume that the deoxidizing agent isl ing obtained, has a purity of 99.97%. Whenother deoxidizing 'agents are employed a curve similar to the one shown in Fig. 1 may be prepared. It has been found that the original copper (commercial copper) employed has a purity of about 99.90% and that during the treatment, or manufacturing, the purity reduces to about 99.50 due to some absorption of oxygen and of impurities from the furnace lining. Before the completion of our improved process this is raised so that the final result has the purity above mentioned, i. e., 99.97% or better.

The curve shown in Fig. 1 also shows the temperature at which the metal should be poured. Some of the best results, however. follow when the metal is poured at or above the temperature of 2270o F.

After the metal has been deoxidized vthere is added a small proportion of certain materials or substances, preferably in powdered form, which materials are intended to serve as a nuclei for the formation of largecrys-V tals in the metal. Preferably there is added loo 1/8 of 1% to 1/4 of 1% of these materials or i substances and the metal is preferably stirred in order to thoroughly mix these ysubstances `into the mass. This step is of importance as it has a bearing on the tineness or purity of the final metal.

The mixing in an electrical furnace of the4 rotating type has been found most excellent. l

Several different substances have been em ployed as the nuclei forming material. In one instance we have found that goodresults may be obtained by using aluminum magnesium Vsilicates such as mica or alberene stone. Excellent results followed the use of zirconium silicate, (ZrSiO4), barium sulphate I (BaSOl), sodium aluminate (Na2AlO4),

molybdenum sulphide (M082), vanadium pentoxide (V205), and graphite. These substances, themselves, it will be noted, are relatively insoluble in molten steel, and when they are combined with the deoxidized base metal, as herein described, produce the advantageous` new metal which resists the action of the oxygen lance.

the temperature of the mass is about 22700 F.

The metal in the molds is allowed to cool very slowly. Care should be taken to cover the metal with a suitable non-conducting substance after pouring, especially if the casting is small. The cooling is an important step in the preparation of this metal, as above noted, for the purpose of permitting the formation of the large size grain crystals. It is preferred to cool at a predetermined rate in w order that the cooling may be satisfactorily accomplished.

Reference is now made to Fig. 2 of the drawings in which there is shown a cooling curve that permits the formation of the de` sired crystalline structure. It` will be noted that in this curve the approximate point of freezing of the metal is pointed out, and the Various changes in the curve show approximate temperatures where there are Various changes being made in the crystalline structure during the cooling.

It has been found that the best results are obtained when there is special controlling of the cooling until the temperature reaches about 13000 F. The cooling from 13000 F.

to 700 F. is not quite` so important, but should be controlled asto the rate of cooling. Below 700 F. the rate of cooling may be rapid. r,

If the casting cools too quickly or in such a manner as not to give-a satisfactory result it may be subsequently heat treated and the recooling controlled in accordance with the curve in Fig. 2 of the drawings.

In the case 'of such subsequent heat treatment, the casting should be brought to a temperature of approximately 19000 F. and held at that point until such time as the Whole casting has been raised to this temperature.

It should then be allowed to cool very slowly y, until the temperature reaches about 7000 F. f and fromthis point down it may be allowed to cool quickly if desired. VVhencertain materials in a pulverulent condition are added to the metal in molten ,condition and thoroughly stirred therewith it has been found that the cooling curve Yof the metalwill rise after the same has solidifled. This rise in temperature usually indicates av crystalline change. Such crystalline changes are shown in Fig. 3 of the drawings where curve 1 shows the cooling curve of a metal which has been deoxidized by cupro silicon and has had added to it alberene stone @o or the like as the nuclei forming substance.

ing substance.

Examination of this new metal under the microscope w1ll show a peculiar and characteristic crystalline structure. This structure shows large grains and a deposit of a dark material in the grain boundaries.

In disclosing the advantages of the process herein set forth there is illustrated in Figs. 4, 5 and 6 of the drawings diagrammatic representations of microscopic pictures of various samples of metal. In Fig. 4 there is illustrated the ordinary cast copper having therein no nuclei forming substance such as alberene stone or graphite and there is in that illustration evidence of solid solution (alloying) as shown by mixed crystals appearing in the metal. It will be noted that there are a large number of relatively small size crystals such as 3, 4 and 5 and the like.

The representation shown in Fig. 5 is a magnified View of cast copper made in ac- )cordance with this process wherein alberene stone or the like was used as the added material for nuclei forming purposes. In that figure it will be seen that there are large grain crystals, portions thereof being illustrated at 6, 7 and 8. It will be noted that the grain boundaries are very clearly defined and that there is shown in the boundaries the amorphous material 9 which varies in size and,

therefore, amount. It will therefore be noted that the amorphous material throughout the grain boundaries creates an envelope around eachgrain. This is t-he material which is especially resistant to an attack by local high heat. In Fig. 6 there is shown a crystalline structure of cast copper made in accordance with the process hereinA where the nuclei forming material is graphite. In this instance also there is noted the large grain crystals 10, 11, 12 and 13 while the boundaries between the crystals are clearly defined and the amorphous material 14 is present.

For the purpose of comparison the reproduction in Figs. 4,' 5 and 6 are taken from photo micrographs of the same degree of magnification, i. e. 150 magnification.

The new metal herein disclosed is a material improvement on the metal disclosed in our copending application, alloys and material employing the same, led May 19, 1923, Serial No. 640,226, and the divisional application therefrom, refractory materials and process of producing the same, filed January 16, 1925, Serial No. 2,863. In the present processand product there is added a nuclei forming substance. This is not true of the process and product set forth and claimed in our copending applications, and also there is a smaller amount of cupro silicon employed in the present process. In' the process dev scribed in the copending applications there.

is an alloying of the material which alloying reduces the heat conductivity of the resulting metal. This feature is particularly undel sirable in the present process for the present product is substantially free of oxides and other impurities. Another distinction of the present product from that of the product in the copending applications is that the present product is of a fewer number of large size grain crystals while the former product is made up of a large number of small size crystals. Inthe copending applications by reason of the small amount of carbon there is considerable oxide in the resulting metal, while in the present metal by using a different amount of carbon the oxide becomes reduced so that a substantially pure unalloyed copper is obtained and consequently a materially larger grain structure, which is of l advantage in increasing the heat conductivity of the new metal over the metal before being` subjected to this process. All of these features are of very material advantage in the manufacture of metals and plates formed thereof, and which are exceptionally desiray ble in producing Vaults arid safes. In addition, there is also a special advantage of the new metal with its high electrical conductivity for it may be used for power transmission lines and the like to a material advantage and saving.

- We claim:

l. A process of forming a new metal which consists in raising a base metal to a molten condition, deoXidizing said metal, adding a substance relatively insoluble in molten steel, and cooling in a manner to cause the substanceto be deposited in the amorphous material in the grain boundaries of the crystals.

2. A process of forming a new metalwhich consists in raising a base metal to a molten condition, deoxidizing said metal, adding M3 of 1% to l of 1% of alberene stone, and Cooling in a manner to cause the said alberene'stone to be deposited in the amorphous material in the grain boundaries of the crystals, said coolingbeing carried on at a predetermined rate that permits the formation of crystalline structure with the majority of crystals of relatively large size.

3. A process of forming a new metal which consists vin raising a metal ofA high conduc.

tivity to molten condition, adding a sufficient quantity of material that will deoxidize said metal without leaving an excess'to alloy therewith, adding a nuclei' forming substance, and cooling in a manner to permit the formation of large crystals and the deposit of said nuclei forming substance in the amorphous material of the grain boundaries.

4. A process of forming a new metal which consists in raising commercial copper to a molten condition, deoxidizing said copper, adding nuclei forming substances, and cooling at a rate that gives a crystalline structure with the majority of crystals of relatively large size and the deposit of said nuclei forming substance in the amorphous material of the grain boundaries.

5. In the process of treating copper, the step of adding 1/8 of 1% to 1%; of 1% ofnuclei forming substances.

6. The process of forming a new metal which consists in raising commercial copper to a molten condition, deoxidizing said copper, adding L@ of 1% to 1%1 of 1% of nuclei forming substances, and cooling in a manner to permit the formation of large crystals and the deposit of said nuclei forming substance in the amorphous material of the grain boundaries. i

7 In thelprocess of treating commercial copper to improve its purity and crystalline structure, the steps of raising the copper to a molten condition, adding a deoxidizing.` agenuthe amount of which is dependent upon the temperature of the copper, adding a vnuclei forming substance, andcooling whereby the said nuclei forming substance deposits in the amorphous material of the grain boundaries.

8. The process of increasing the purity and grain structure of copper, which consists in raising the copper to a molten condition, adj ding commercial cupro silicon to deoxidize said copper, the amount of said `cupro silicon being dependent upon the temperature of the molten copper at the time of adding said cuprosilicon, addin lgof 1% to lof 1% of nuclei forming su stances, and cooling in va manner'to permit the formation ofrlarge crystals and the'deposit of said nuclei form-l ing substance in the amorphous material of the grain boundaries. J

9. The process of increasing the purity and resistance to local high heat of copper,- which Y consists in melting copper in an'y electric furnace, covering the surface thgeof with powv dered charcoal to prevent oxidization, adding a predetermined amount of 20% cupro silicon to deoxidize said copper without alloying therewith, the amount of said cupro silicon being governed by the temperature of said copper at the timeofadding the same, stirring, adding a nuclei forming material in the quantity of 1/8 of 1% to 1%,c of 1%, pouring said material at a temperature above 2270 F., covering the copper after pouring with non-conductivesubstances, and cooling slowly to permit the formation oflarge crysy aluminum magnesium silicate deposited in tals and permit Ithe depositof lsaid. nuclei 'l forming' substance inthe amorphous matter of the grain boundaries.

10. A metal of high conductivity which has been` deoxidized by cupro silicon and which has large grain size and has an the amorphous material inthe grain boundaries.

11. Cast copper plate having large crystalline structure and which has been deoXidized-by employing a predetermined amount of 20% c'upro silicon and which has had added thereto from 1/8 of 1% to l@ of y1% December,

alberene stone.

12. An article of manufacture being cope per with substantially all the oxides removed, said article having relatively large crystals and having a substance relatively insoluble in moltensteel deposited in the amorphous material in the grain boundaries.

This specification si JOSEPH G. DONALDSON. HENRY L. GOLES. v

gned this 14th day of 

